Battery Module

ABSTRACT

A battery module including: a battery stack of battery cells having opposite ends to which a plurality of electrode tabs are connected; end-side bus bar assemblies formed at opposite ends of the battery stack, respectively, and electrically connecting the electrode tabs of the battery cells; and a case accommodating the battery stack and the end-side bus bar assemblies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/848,571 filed on Apr. 14, 2020, which claimspriority under 35 U.S.C. § 119 to Korean Patent Application No.10-2019-0043975, filed on Apr. 15, 2019, in the Korean IntellectualProperty Office. The disclosure of each of the foregoing applications isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The following disclosure relates to a battery module, and moreparticularly, to a battery module including an ultra-long battery cellhaving a large width.

BACKGROUND

A secondary battery has been prominent as a power source of an electricvehicle (EV), a hybrid electric vehicle (HEV), and the like, that havebeen suggested for solving air pollution caused by an existing gasolinevehicle, a diesel vehicle, or the like, using fossil fuel. It isrequired to improve an energy density and diminish a spatial restrictionin order to load the secondary battery in a vehicle, and in this regard,a long battery cell, in which an edge between electrode tabs is muchlonger than an edge where the electrode tabs are positioned, has beensuggested. A general battery cell has a width of 300 mm or less.Whereas, the long battery cell has a width of 600 mm, and an ultra-longbattery cell is designed to have a width of 600 mm or more.

However, the long battery cell or the ultra-long battery cell has aproblem that a cell internal resistance is increased due to a largelength between the electrode tabs, which causes an increase in powerloss. In addition, since a difference in temperature between regions ofthe battery cell is large, performance of the battery cell deterioratesand a battery life is reduced, and the ultra-long battery cell may bebent due to its own weight.

Therefore, in order to commercialize the battery module including theultra-long battery cell, an electrical structure capable of reducing thecell internal resistance, a cooling system capable of resolving aheating problem, an assembling structure capable of improving astructural stability, and the like are required.

SUMMARY

An embodiment of the present invention is directed to providing abattery module structure in which a long battery cell or ultra-longbattery cell may be modularized without increasing a battery cellinternal resistance.

Another embodiment of the present invention is directed to providing abattery module structure capable of improving cooling efficiency of along battery cell or ultra-long battery cell and structural stability.

In one general aspect, a battery module includes: battery cells 100 eachhaving opposite ends to which a plurality of electrode tabs areconnected; a battery stack 200 formed by stacking the battery cells 100;end-side bus bar assemblies 300 formed at opposite ends of the batterystack 200, respectively, and connecting the electrode tabs of thebattery cells 100 in series; transverse bus bar assemblies 400 eachconnecting electrode tabs connected to opposite ends of an uppermostbattery cell 100 or a lowermost battery cell 100 in the battery stack200, in parallel; and a case 500 accommodating the battery stack 200,the end-side bus bar assemblies 300, and the transverse bus barassemblies 400.

The end-side bus bar assembly may include a plurality of end-side busbars 320 electrically connecting electrode tabs positioned at the sameend, and an end-side bus bar plate 310 enclosing the end-side bus bars320 and coupled to the battery stack 200.

The end-side bus bars 320 may include a first end-side bus bar 321electrically connecting the electrode tabs positioned at one end of thebattery stack 200, and a second end-side bus bar 322 electricallyconnecting the electrode tabs positioned at the other end of the batterystack 200.

The first end-side bus bar 321 and the second end-side bus bar 322 mayeach have slits into which the electrode tabs are fitted, respectively.

The transverse bus bar assembly 400 may include a transverse bus bar 420electrically connecting the electrode tabs, and transverse bus barplates 410 coupled to the battery stack 200 and accommodating thetransverse bus bar 420.

The transverse bus bar plate 410 may include a transverse bus baraccommodating groove 412 in which the transverse bus bar 420 isaccommodated, and a protruding bead 411 formed at an edge of thetransverse bus bar accommodating groove 412 and absorbing an externalimpact.

The transverse bus bar 420 may include electrode tab connection portions421 coupled to the electrode tabs, respectively, and a transverseconnection portion 422 electrically connecting a pair of electrode tabconnection portions 421.

The end-side bus bar assembly 300 may connect the plurality of electrodetabs positioned at one end or the other end of the battery stack 200 inseries, and the transverse bus bar assembly 400 may connect a pair ofelectrode tabs connected in series by the end-side bus bar assembly 300,in parallel.

The end-side bus bar assembly 300 may electrically connect electrodetabs with the same polarity positioned at one end and the other end ofthe end-side bus bar assembly 300, respectively.

The transverse bus bar assemblies 400 disposed on a top portion and abottom portion of the battery stack 200 may electrically connectelectrode tabs with opposite polarities.

The battery stack 200 may further include heat radiation plates 210accommodating the battery cells 100.

The heat radiation plate 210 may include upper and lower connectionportions 214 for coupling adjacent heat radiation plates 210 in a casewhere the heat radiation plates 210 are stacked in a state in which thebattery cells 100 are accommodated.

The battery module may further include a buffer pad 230 provided betweenthe battery cells 100 facing each other when the heat radiation plates210 are stacked.

The heat radiation plate 210 may further include an adhesive 220provided on contact surfaces, the contact surfaces being in contact withthe accommodated battery cells 100, respectively.

A side assembling groove 213 into which a protrusion formed on the case500 is inserted may be formed in an outer side surface of the heatradiation plate 210 that faces the case 500.

The case may include terminal plates 511 each including an outputelectrode tab electrically connected to the end-side bus bar assembly300.

The case 500 may further include end-side case covers 510 each enclosingthe terminal plate 511 and each having an opening portion through whichthe output electrode tab passes.

The case 500 may include side case covers 520 coupled to side surfacesof the battery stack 200, and cooling plates 540 coupled to the sidecase covers 520, respectively, and forming cooling passages,respectively.

The side case cover 520 may include a side protrusion portion 521inserted into a groove formed in the end-side bus bar assembly 300.

The case 500 may include upper and lower case covers 530 coupled to anupper surface of the transverse bus bar assembly 400 coupled to an upperend of the battery stack 200 and a lower surface of the transverse busbar assembly 400 coupled to a lower end of the battery stack 200,respectively.

A curved portion 130 may be formed in the electrode tab coupled to thebattery cell 100.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a battery module according tothe present invention.

FIG. 2 is an exploded perspective view illustrating the battery moduleaccording to the present invention.

FIG. 3 is a perspective view illustrating a state in which bus barassemblies are connected to a battery stack according to the presentinvention.

FIG. 4 is a perspective view illustrating a battery cell of the batterymodule according to the present invention.

FIG. 5 is a front view and a rear view illustrating a state in which thebus bar assemblies are connected to the battery stack according to thepresent invention.

FIG. 6 is an exploded perspective view illustrating a transverse bus barassembly of the battery module according to the present invention.

FIG. 7 is a perspective view illustrating a state in which a pair ofbattery cells according to the present invention is coupled to a heatradiation plate.

FIG. 8 is a cross-sectional view taken along line A-A′ illustrating thestate in which the pair of battery cells according to the presentinvention is coupled to the heat radiation plate.

FIG. 9 is a cross-sectional view illustrating the battery moduleaccording to the present invention.

FIG. 10 is a partially enlarged view illustrating an end portion of thebattery cell of the battery module according to the present invention.

FIGS. 11 and 12 are each a conceptual view illustrating a couplingstructure of an electrode tab and an end-side bus bar of the batterymodule according to the present invention.

FIG. 13 is an exploded perspective view illustrating an end-side bus barassembly of the battery module according to the present invention.

FIG. 14 is an exploded perspective view illustrating a terminal plate ofthe battery module according to the present invention.

FIG. 15 is a front perspective view and a rear perspective view eachillustrating a case cover of the battery module according to the presentinvention.

DETAILED DESCRIPTION OF MAIN ELEMENTS

100: Battery cell

110: Positive electrode tab

120: Negative electrode tab

130: Curved portion

200: Battery stack

210: Heat radiation plate

213: Side assembling groove

214: Upper and lower connection portion

220: Adhesive

230: Buffer pad

300: End-side bus bar assembly

310: End-side bus bar plate

320: End-side bus bar

400: Transverse bus bar assembly

410: Transverse bus bar plate

420: Transverse bus bar

500: Case

521: Side protrusion portion

540: Cooling plate

DETAILED DESCRIPTION OF EMBODIMENTS

Various advantages and features of exemplary embodiments of the presentinvention and methods accomplishing them will become apparent from thefollowing description of the exemplary embodiments with reference to theaccompanying drawings. However, the present invention is not limited tothe exemplary embodiments to be described below, but may be implementedin various different forms, these exemplary embodiments will be providedonly in order to make the present invention complete and allow thoseskilled in the art to completely recognize the scope of the presentinvention, and the present invention will be defined by the scope of theclaims. Throughout the specification, like reference numerals denotelike elements.

Hereinafter, in describing the exemplary embodiments of the presentinvention, when it is decided that a detailed description for the knownfunctions or components may unnecessarily obscure the gist of thepresent invention, the detailed description will be omitted. Further,the following terminologies are defined in consideration of thefunctions in the exemplary embodiments of the present invention and maybe construed in different ways by the intention of users and operators.Therefore, these terms should be defined on the basis of the contentsthroughout the present specification.

Hereinafter, a battery module according to the present invention will bedescribed with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating a battery module 1000including a long battery cell or ultra-long battery cell according tothe present invention, and FIG. 2 is an exploded perspective viewillustrating the battery module 1000 according to the present invention.

Referring to FIGS. 1 and 2 , the battery module 1000 according to thepresent invention includes a battery stack 200 formed by stackingbattery cells 100, bus bar assemblies electrically connecting thebattery cells 100 forming the battery stack 200, and a case 500accommodating and protecting the battery stack 200 and the bus barassemblies 300 and 400. The bus bar assemblies include end-side bus barassemblies 300 formed at opposite ends of the battery stack 200 andelectrically connecting electrode tabs of the plurality of battery cells100, and transverse bus bar assemblies 400 each electrically connectingelectrode tabs connected to opposite ends of the uppermost battery cell100 or the lowermost battery cell 100 in the battery stack 200. Here,the case 500 may include terminal plates 511 electrically connected tothe end-side bus bar assemblies 300, respectively, and each including anoutput electrode tab exposed to the outside, end-side case covers 510coupled to the terminal plates 511, respectively, and each having anopening portion through which the output electrode tab passes, side casecovers 520 coupled to side surfaces of the battery stack 200,respectively, cooling plates 540 coupled to the side case covers 520,respectively, and forming a cooling passage, and upper and lower casecovers 530 coupled to an upper surface of the transverse bus barassembly 400 coupled to an upper end of the battery stack 200 and alower surface of the transverse bus bar assembly 400 coupled to a lowerend of the battery stack 200, respectively.

Specifically, the end-side bus bar assemblies 300 are coupled to one endand the other end of the battery stack 200, and the transverse bus barassemblies 400 are coupled to an upper side and a lower side of thebattery stack 200, such that a pair of electrode tabs formed at oppositeends of a battery cell 100 are electrically connected to each other.Output terminals 511-1 of the terminal plates 511 coupled to theend-side bus bar assemblies 300, respectively, are electricallyconnected to the transverse bus bar assemblies 400 to allow a user touse power of the battery module through the output terminals 511-1.Then, the end-side case covers 510 are coupled to outer surfaces of theterminal plates 511, respectively, the side case covers 520 are coupledto the side surfaces of the battery stack 200, respectively, and theupper and lower case covers 530 are coupled to the upper surface of thetransverse bus bar assembly 400 coupled to the upper end of the batterystack 200 and the lower surface of the transverse bus bar assembly 400coupled to the lower end of the battery stack 200, respectively, toprotect the respective components electrically connected to each other,and the cooling plates 540 are coupled to the side case covers 520,respectively, to cool the battery cells 100 positioned inside the case500.

FIG. 3 is a perspective view illustrating a state in which the bus barassemblies are connected to the battery stack according to the presentinvention, and FIG. 4 is a perspective view illustrating the batterycell 100 forming the battery stack according to the present invention.Referring to FIG. 3 , the battery cell 100 according to the presentinvention is a long battery cell or ultra-long battery cell in which alength of an edge where the electrode tables are positioned is muchlonger than a length of an edge between the electrode tabs. In thebattery module according to the present invention, the end-side bus barassemblies 300 and the transverse bus bar assemblies 400 are coupled tothe battery stack 200, such that the plurality of battery cells 100 areelectrically connected to one another. Specifically, in case of astructure in which one electrode tab is formed at each of opposite endsof the battery cell 100, when a width of the battery cell 100 isincreased, a length between electrode tabs is increased, such that aninternal resistance is increased, which is problematic. Therefore,according to the present invention, a first positive electrode tab 111and a first negative electrode tab 121 are formed at one end of thebattery cell 100 forming the battery stack 200, and a second positiveelectrode tab 112 and a second negative electrode tab 122 are formed atthe other end of the battery cell 100 as illustrated in FIG. 4 , suchthat the positive electrode tab 111 or 112 and the negative electrodetab 121 or 122 are positioned at both ends of the battery cell 100.

Further, since a plurality of battery cells 100 form the battery stack200, electrode tabs positioned at the same end are connected in seriesby the end-side bus bar assembly 300 to obtain a higher voltage. Theleft side of FIG. 5 illustrates a connection state when viewed from thefront, in which the first positive electrode tab 111 and the firstnegative electrode tab 121 positioned at one end of the battery stack200 are connected in series through a first end-side bus bar 321. Theright side of FIG. 5 illustrates a connection state when viewed frombehind, in which the second positive electrode tab 121 and the secondnegative electrode tab 122 positioned at the other end of the batterystack 200 are connected in series through a second end-side bus bar 322.As a result, the user may output a higher voltage through the stackedbattery cells 100.

Here, in a case where, among the electrode tabs positioned at one endand the other end of the battery cell 100, only an electrode tabpositioned at any one end is activated, a current density in a specificregion of the one end at which the activated electrode tab is positionedis increased, such that the specific region of the battery cell 100 towhich the activated electrode tab is coupled is overheated as comparedwith other regions, and a surface pressure is increased, and thusdendrites may be formed. Accordingly, in the present invention, it ispreferable that an electrode tab positioned at one end and an electrodetab positioned at the other end are connected in parallel through thetransverse bus bar assembly 400 as illustrated in FIGS. 3 and 5 .Specifically, the first positive electrode tab 111 and the firstnegative electrode tab 121 are formed at one end of the battery cell100, and the second positive electrode tab 112 and the second negativeelectrode tab 122 are arranged in a horizontally reversed manner withrespect to the first positive electrode tab 111 and the first negativeelectrode tab 121, at the other end of the battery cell 100 asillustrated in FIG. 4 . Therefore, the transverse bus bar assembly 400coupled to the upper end of the battery stack 200 as illustrated in FIG.5 electrically connects the first positive electrode tab 111 and thesecond positive electrode tab 112, or the first negative electrode tab121 and the second negative electrode tab 122, and the transverse busbar assembly 400 coupled to the lower end of the battery stack 200connects electrode tabs with opposite polarities, such that electrodetabs positioned at different ends and connected in series through theend-side bus bar assembly 300 are connected in parallel.

The transverse bus bar assembly 400 connecting electrode tabs positionedat different ends in parallel is electrically connected to the outputelectrode tabs of the terminal plates 511 coupled as described above,and all electrode tabs positioned at one end and the other end of thebattery cell 100 are activated when the user uses the output electrodetabs. Therefore, an uneven temperature distribution phenomenon due to anincrease in a current density caused when only an electrode tab coupledto any one end is activated may be significantly reduced and formationof the dendrites may be prevented. Further, it is a matter of coursethat the transverse bus bar assembly 400 coupled to a top portion of thebattery stack 200 and the transverse bus bar assembly 400 coupled to abottom portion of the battery stack 200 may be connected through thefirst end-side bus bar 321 and the second end-side bus bar 322 asillustrated in FIG. 5 .

FIG. 6 is an exploded perspective view illustrating the transverse busbar assembly of the battery module according to the present invention.

Referring to FIG. 6 , the transverse bus bar assembly 400 may include atransverse bus bar 420 electrically connecting electrode tabs, andtransverse bus bar plates 410 coupled to the battery stack 200 andaccommodating the transverse bus bar 420. Specifically, in a case wherethe transverse bus bar 420 is exposed to the outside, the transverse busbar 420 may be damaged by an external impact. Therefore, according tothe present invention, the transverse bus bar plates 410 enclose thetransverse bus bar 420 to protect the transverse bus bar 420.

Further, the transverse bus bar plate 410 may include a transverse busbar accommodating groove 412 in which the transverse bus bar 420 isaccommodated, and a protruding bead 411 formed at an edge of thetransverse bus bar accommodating groove 412 to increase exteriorrigidity and absorb an impact. The transverse bus bar 420 may includeelectrode tab connection portions 421 coupled to the electrode tabs,respectively, and a transverse connection portion 422 electricallyconnecting a pair of electrode tab connection portions 421.Specifically, the transverse bus bar accommodating groove 412 in whichthe transverse connection portion 422 is accommodated is formed in aninner surface of at least one of the transverse bus bar plates 410divided into an upper transverse bus bar plate and a lower transversebus bar plate. When the upper transverse bus bar plate and the lowertransverse bus bar plate are coupled to each other in a state in whichthe transverse connection portion 422 is inserted into the transversebus bar accommodating groove 412, the transverse bus bar plates 410enclose the transverse connection portion 422 to protect the transverseconnection portion 422 from an external impact. The electrode tabconnection portions 421 formed at opposite end portions of thetransverse connection portion 422 in a length direction are eachpositioned on tab exposing holes 413 formed in the lower transverse busbar plate 410, respectively, and are each connected to the firstend-side bus bar 321 or the second end-side bus bar 322 into whichelectrode tabs of neighboring battery cells 100 are fitted when thetransverse bus bar assemblies 400 are coupled to the upper side and thelower side of the battery stack 200, respectively.

Here, the transverse bus bar plate 410 may include the protruding bead411 formed at the edge of the transverse bus bar accommodating groove412 to more effectively protect the accommodated transverse bus bar 420,and the protruding bead 411 may have a lattice-shaped structure toincrease an external impact absorption rate.

FIG. 7 is a perspective view illustrating a state in which a pair ofbattery cells according to the present invention is coupled to a heatradiation plate, and FIG. 8 is a cross-sectional view of FIG. 7 .

Referring to FIG. 7 , the battery module according to the presentinvention may further include a heat radiation plate 210 accommodatingthe battery cells 100 at an upper side and a lower side of the heatradiation plate 210, respectively. Specifically, since performance ofthe battery cell 100 deteriorates and the battery life is reduced in acase where a temperature is increased to a certain point or higher, theheat radiation plate 210 having an “H”-letter shaped cross-sectionalstructure is positioned between the battery cells 100 to facilitatecooling of the battery cell 100.

Here, the heat radiation plate 210 may include a central heat radiationplate 210A which is in contact with an upper surface or a lower surfaceof each of the battery cells 100 positioned on the upper side and thelower side of the heat radiation plate 210, and edge heat radiationplates 210B which surround side surfaces of the battery cells 100 asillustrated in FIG. 8 . Further, heat generated from the battery cell100 may be more efficiently transferred to the heat radiation plate 210and then radiated to the outside by providing an adhesive 220 on a firstcontact surface 211 of the central heat radiation plate 210A that is incontact with the battery cell 100, and a second contact surface 212 ofthe edge heat radiation plate 210B that is in contact with the batterycell 100.

Upper and lower connection portion 214 for coupling, in a case where aplurality of heat radiation plates 210 are stacked, the heat radiationplate 210 to a heat radiation plate 210 positioned thereon and a heatradiation plate 210 positioned thereunder may be formed at an upper endportion and a lower end portion of the edge heat radiation plate 210B,respectively. A side assembling groove 213 into which a protrusion ofthe case 500 is inserted may be formed in a side surface of each of theedge heat radiation plates 210B. Detailed structures of the sideassembling groove 213 and the Upper and lower connection portion 214will be described in more detail later.

FIG. 9 is a cross-sectional view of the battery module according to thepresent invention. Referring to FIG. 9 , in the battery module 1000, thebattery stack 200 may be formed by accommodating the battery cells 100at the upper side and the lower side of each of the heat radiationplates 210, respectively, and then vertically stacking the heatradiation plates 210. The side case covers 520 may be coupled to theside surfaces of the battery stack 200, and then the upper and lowercase covers 530 are coupled to the side case covers 520 to enclose andprotect the battery stack 200. In addition, the cooling plates 540 arecoupled to the side case covers 520, respectively, such that a coolantor a refrigerant may flow close to the side case covers 520.

Specifically, the Upper and lower connection portion 214 of the heatradiation plate 210 include a coupling protrusion 214-1 and a couplinggroove 214-2 into which the coupling protrusion 214-1 is fitted andfixed as illustrated in FIG. 8 , and the heat radiation plates 210 arestacked to form one battery stack 200 as illustrated in FIG. 9 . Inaddition, since the battery stack 200 has a structure in which the heatradiation plates 210 are stacked and the stacked heat radiation plates210 may be uncoupled at the time of vertical movement, the sideassembling groove 213 is formed in an outer side surface of the heatradiation plate 210, a side protrusion portion 521 fitted into the sideassembling groove 213 is formed on the side case cover 520, and the sideprotrusion portion 521 is fitted into the side assembling groove 213,thereby restricting the vertical movement of the heat radiation plate210. In addition, as the side protrusion portion 521 is fitted into theside assembling groove 213, a contact area between the heat radiationplate 210 and the side case cover 520 is increased, and thus heat of thebattery cell 100 is more effectively transferred to the side case cover520 through the heat radiation plate 210. The heat transferred to theside case cover 520 is absorbed by a coolant or refrigerant flowingthrough a cooling passage 541 formed by the cooling plate 540 coupled tothe side case cover 520 and having a concave-convex cross-sectionalshape.

Here, the cooling passage 541 is formed on the cooling plate 540, and isformed by a plurality of pattern protrusions 542 protruding inwardly toface the side case cover 520. Since a cross-sectional area and a shapeof the cooling passage 541 are changed depending on a shape andarrangement of the pattern protrusion 542, it is possible to allow thecoolant or refrigerant passing through the cooling passage 541 to form avortex at a specific region by adjusting the shape or arrangement of thepattern protrusion 542. Specifically, in a case where the coolingpassage 541 has a linear structure, a time for which the coolant orrefrigerant remains in the cooling passage 541 is reduced, and thus heatexchange efficiency may be reduced. Therefore, according to the presentinvention, the cooling passage 541 has a curved structure with thepattern protrusion 542, such that the coolant or refrigerant passingthrough the cooling passage 541 may hit the pattern protrusion 542 andform a vortex. Further, the shape and arrangement of the patternprotrusion 542 for allowing the coolant or refrigerant passing throughthe cooling passage 541 to form a vortex may vary. According to anexemplary embodiment, a pattern protrusion arranged on one end of thecooling plate 540 and a pattern protrusion adjacent thereto may bemisaligned in a vertical direction to allow the coolant or refrigerantpassing through the cooling passage 541 to hit the pattern protrusions542 and form a vortex.

Further, when the battery stack 200 is formed by stacking the heatradiation plates 210, an empty space may be formed between battery cells100 accommodated in different heat radiation plates 210, respectively.In such an empty space, a buffer pad 230 for preventing the battery cell100 from escaping from the heat radiation plate 210 or preventing thebattery cells 100 from colliding with each other may be provided.

FIG. 10 is a partially enlarged view of the battery cell of the batterymodule according to the present invention, and FIGS. 11 and 12 are eacha conceptual view illustrating a coupling structure of the electrode taband the end-side bus bar. Referring to FIG. 10 , it is preferable that acurved portion 130 is formed in the electrode tab coupled to the batterycell 100. Specifically, the first positive electrode tab 111, the secondpositive electrode tab 112, the first negative electrode tab 121, andthe second negative electrode tab 122 are formed in the battery cell 100as illustrated in FIG. 4 , and the electrode tabs T are fitted intoslits formed in the first end-side bus bar 321 or the second end-sidebus bar 322 and then welded to the first end-side bus bar 321 or thesecond end-side bus bar 322 as illustrated in FIG. 11 . The curvedportion 130 is formed in the electrode tab T to absorb an externalvibration or impact, thereby significantly reducing a damage to thecoupling between the electrode tab T and the end-side bus bar, or adamage to the electrode tab T. Here, when the electrode tab T isinserted into the slit formed in the end-side bus bar as illustrated inFIG. 11 , the end-side bus bar is seated on the curved portion 130, andthus the curved portion 130 may be used to facilitate the welding. Inaddition, when the electrode tab T and the end-side bus bar 321 or 322is welded by using a laser, the curved portion 130 may prevent the laserpassing through the slit formed in the end-side bus bar from beingdirectly irradiated to the battery cell 100. The battery cell 100 mayfurther include a sealant portion 140 which seals a position where theelectrode tab T is led out and encloses a connection portion of theelectrode tab T led out from the battery cell 100 to ensure anelectrical insulating state. The sealant portion 140 may enclose thecurved portion 130 and a region between the curved portion 130 and anelectrode tab lead-out portion, except for an end portion inserted intothe slit of the end-side bus bar.

FIG. 13 is an exploded perspective view illustrating the end-side busbar assembly 300 of the battery module according to the presentinvention. Referring to FIG. 13 , the end-side bus bar assembly 300 mayinclude an end-side bus bar plate 310 coupled to the battery stack 200,and end-side bus bars 320 coupled to the end-side bus bar plate 310 andconnecting the positive electrode tab and the negative electrode tab inseries or in parallel as described above. Specifically, the end-side busbar plate 310 encloses the end-side bus bars 320 to prevent the end-sidebus bars 320 from being exposed to the outside.

FIG. 14 is an exploded perspective view illustrating the terminal plate511 of the battery module according to the present invention. Referringto FIG. 14 , the terminal plate 511 includes an outer protector 511-2 inwhich an accommodating portion is formed, an output terminal 511-1fitted into the accommodating portion of the outer protector andelectrically connected to the end-side bus bar 320, and an innerprotector 511-3 coupling the output terminal 511-1 fitted into theaccommodating portion with the outer protector 511-2. Specifically, theouter protector 511-2 and the inner protector 511-3 enclose the outputterminal 511-1 electrically connected to the end-side bus bar 320 toprevent a damage caused by an external impact, and significantlydecreasing a surface area exposed to the outside, thereby improving aninsulating property.

FIG. 15 is a perspective view illustrating a pair of end-side casecovers 510 coupled to the terminal plates 511, respectively. Referringto FIG. 15 , the end-side case cover 510 includes a cooling passageconnection portion 510-1 communicating with the cooling passage 541formed on the cooling plate 540. Specifically, according to the presentinvention, since the cooling plates 540 are provided on one side surfaceand the other side surface of the battery stack 200, respectively, andthe cooling passages 541 in which the refrigerant or coolant moves areformed on the cooling plates 540, respectively, the cooling passages 541separate from each other are connected to each other through the coolingpassage connection portion 510-1, such that a circulation passage, inwhich the refrigerant or coolant may move along an edge of the batterymodule and cool the battery, is formed.

With the above-described configuration, in the battery module accordingto the present invention, a stable electrical connection may be madewithout increasing an internal resistance by forming a plurality ofelectrode tabs at each of opposite ends of the long battery cell orultra-long battery cell, connecting bus bars positioned at opposite endsof the stacked ultra-long battery cells in series, and connecting theremaining electrode tabs of the uppermost battery cell or lowermostbattery cell in parallel through the transverse bus bar assembly.

Further, as a plurality of positive electrode tabs and a plurality ofnegative electrode tabs are formed in one cell, a direct currentinternal resistance (DCIR) of the cell may be reduced.

Since the battery cell may be more effectively cooled by using the heatradiation plate and the cooling plate, it is possible to improve theperformance of the battery cell and the battery life.

Further, the side case cover and the battery stack are fixed by usingthe side assembling groove of the heat radiation plate, therebypreventing the ultra-long battery cell from being bent.

The present invention should not be construed to being limited to theabove-mentioned exemplary embodiment. The present invention may beapplied to various fields and may be variously modified by those skilledin the art without departing from the scope of the present inventionclaimed in the claims. Therefore, it is obvious to those skilled in theart that these alterations and modifications fall in the scope of thepresent invention.

What is claimed is:
 1. A battery module comprising: battery cells eachhaving two or more electrode tabs provided at one end and the other end,respectively, and having a length of more than 300 mm from the one endto the other end; a battery stack formed by stacking the battery cells;end-side bus bar assemblies formed at opposite ends of the batterystack, respectively, and connecting the electrode tabs of the batterycells in series or in parallel; transverse bus bar assemblies eachelectrically connecting electrode tabs of an uppermost battery cell or alowermost battery cell in the battery stack; and a case accommodatingthe battery stack, the end-side bus bar assemblies, and the transversebus bar assemblies.
 2. The battery module of claim 1, wherein theend-side bus bar assembly includes a plurality of end-side bus barselectrically connecting the two or more electrode tabs positioned at thesame end, and an end-side bus bar plate enclosing the end-side bus barsand coupled to the battery stack.
 3. The battery module of claim 2,wherein the end-side bus bars include a first end-side bus barelectrically connecting the two or more electrode tabs positioned at oneend of the battery stack, and a second end-side bus bar electricallyconnecting the two or more electrode tabs positioned at the other end ofthe battery stack.
 4. The battery module of claim 3, wherein the firstend-side bus bar and the second end-side bus bar each have slits intowhich the two or more electrode tabs are fitted, respectively.
 5. Thebattery module of claim 2, wherein the transverse bus bar assemblyincludes a transverse bus bar electrically connecting at least one ofthe electrode tabs of the one end and at least one of the electrode tabsof the other end, and transverse bus bar plates coupled to the batterystack and accommodating the transverse bus bar.
 6. The battery module ofclaim 5, wherein the transverse bus bar plate includes a transverse busbar accommodating groove in which the transverse bus bar isaccommodated, and a protruding bead formed at an edge of the transversebus bar accommodating groove and absorbing an external impact.
 7. Thebattery module of claim 6, wherein the transverse bus bar includeselectrode tab connection portions coupled to at least one of theelectrode tabs, respectively, and a transverse connection portionelectrically connecting a pair of electrode tab connection portions. 8.The battery module of claim 1, wherein the end-side bus bar assemblyconnects the electrode tabs positioned at one end or the other end ofthe battery stack in series, and the transverse bus bar assemblyconnects a pair of electrode tabs connected in series by the end-sidebus bar assembly, in parallel.
 9. The battery module of claim 8, whereinthe end-side bus bar assembly connects electrode tabs with oppositepolarities positioned at one end and the other end of the end-side busbar assembly, respectively, in series, or connects electrode tabs withthe same polarity in parallel.
 10. The battery module of claim 9,wherein the transverse bus bar assemblies disposed on a top portion anda bottom portion of the battery stack each electrically connectelectrode tabs with opposite polarities.
 11. The battery module of claim1, wherein the battery stack further includes heat radiation platesaccommodating the battery cells.
 12. The battery module of claim 11,wherein the heat radiation plate includes upper and lower connectionportions for coupling adjacent heat radiation plates in a case where theheat radiation plates are stacked in a state in which the battery cellsare accommodated.
 13. The battery module of claim 12, further comprisinga buffer pad provided between the battery cells facing each other whenthe heat radiation plates are stacked.
 14. The battery module of claim11, wherein a side assembling groove into which a protrusion formed onthe case is inserted is formed in an outer side surface of the heatradiation plate that faces the case.
 15. The battery module of claim 1,wherein the case includes terminal plates each including an outputelectrode tab electrically connected to the end-side bus bar assembly.16. The battery module of claim 15, wherein the case further includesend-side case covers each enclosing the terminal plate and each havingan opening portion through which the output electrode tab passes. 17.The battery module of claim 1, wherein the case includes side casecovers coupled to side surfaces of the battery stack, and cooling platescoupled to the side case covers, respectively, and forming coolingpassages, respectively.
 18. The battery module of claim 17, wherein theside case cover includes a side protrusion portion inserted into agroove formed in the end-side bus bar assembly.
 19. The battery moduleof claim 1, wherein the case includes upper and lower case coverscoupled to an upper surface of the transverse bus bar assembly coupledto an upper end of the battery stack and a lower surface of thetransverse bus bar assembly coupled to a lower end of the battery stack,respectively.
 20. The battery module of claim 1, wherein a curvedportion is formed in the electrode tab coupled to the battery cell.